Theft of trailers and like towed vehicles is a significant problem, and security devices are well known for blocking the drawpin hole in the hitch ring of a trailer to prevent theft of the trailer. For example U.S. Pat. No. 6,467,317 to Hillabush et al. discloses a lock device where upper and lower lock members sandwich the hitch ring and plug the drawpin hole. U.S. Pat. No. 6,862,904 to Hubbart, U.S. Pat. No. 6,598,432 to Dwyer, and U.S. Pat. No. 6,578,392 to Bowman et al. are further examples of similar devices which comprise upper and lower parts locked together with the hitch ring between them to prevent access to the drawpin hole.